Double needle action, needle-bar device in fancy-stitching sewing machine and flat-tang needle therefor



p 1967 BUNSAKU TAKETOMI ,3 7

ION NEEDLE-BAR DEVICE [N FANCY-STITCH [NG DOUBLE NEEDLE ACT SEWINGMACHINE AND FLAT -TANG NEEDLE THEREFOR Filed Oct. 23, 1964 2 Sheets$heetFFG.

FIG.I

INVENTOR BMMMWM'TAMM I P 5, 1967 BUNSAKU TAKETOMI 3,339,507

DOUBLE NEEDLE ACTION, NEEDLE-BAR DEVICE IN FANCYSTITCHING SEWING MACHINEAND FLAT-TANG NEEDLE THEREFOR Filed Oct. 25, 1964 2 Sheets-Sheet f;

RED ED WHITE INVENTOR. B 'OQ kw Tallah 3,339,507 DOUBLE NEEDLE ACTION,NEEDLE-BAR DE- VICE IN FANCY-STITCHING SEWING MA- CHINE AND FLAT-TANGNEEDLE THERE- FOR Bunsaku Taketomi, 9 Z-chome, Uchiyama-cho, Chikusa-ku,Nagoya-shi, Japan Filed Oct. 23, 1964, Ser. No. 406,033 Claims priority,application Japan, Oct. 27, 1963, 38/ 57,798 2 Claims. (Cl. 112-158)ABSTRACT OF THE DISCLOSURE A sewing machine capable of zig-zag movementshaving a vertically reciprocating hollow tubular needle bar with aspecial oscillatory actuating means therewithin which cause two needlespivotally attached to the needle bar, and each having a flat tang of athickness equal to the diameter of the needle shank, to oscillate in ahorizontal plane independently toward and away from each other toproduce symmetrical left and right patterns of stitches.

This invention relates to sewing machines and more particularly to a newdouble needle action, needle-bar device in a fancy-stitching sewingmachine.

Throughout the following disclosure and appended claims, all stateddirections are those as viewed from the sewing machine operatorsposition.

Briefly stated, the present invention provides a double needle action,needle-bar device positioned at and partly enclosed within the left-handend the machine arm of a fancy-stitching sewing machine and comprising:a tubular needle bar driven in vertical reciprocating motion slidinglyin upper and lower guide holes in the machine are by a mechanism drivenin turn by the main driving shaft of the machine, said needle bar beingprovided with a horizontally disposed fiat plate fixed to the lower endthereof and extending rearwardly; left and right needle holders inparallel, side-by-side disposition, respectively pivoted at their rearends for oscillatory motion in the horizontal plane by pins on the lowerrear surface of said flat plate and holding respective sewing needles;and a thin shaft inserted in the tubular needle bar and actuated by thezig-zag sewing mechanism of the machine, said thin shaft having a camfixed to its lower end, which cam is in constant contact with said leftand right needle holders and operates to actuate said needle holders inoscillatory moton about their pivots, whereby the needles are caused tosew a symmetrical pattern in accordance with the actuation by the cam.

The present invention furthermore provides a novel sewing machine needlesuitable for the needle bar device of the invention, which needle has aflattened tang of a thickness equal to the diameter of the needle shank.

The nature, principle, and details of the invention will be more fullyapparent by reference to the following description with respect to apreferred embodiment of the invention, when taken in conjunction withthe accom panying drawings throughout which like parts are designated bylike reference characters, and in which:

FIG. 1 is an end elevational view, with parts cut away, showing theembodiment of the needle-bar device according to the invention;

FIG. 2 is a partial elevational view from the operators position, partlyin section and with parts cut away, of the device shown in FIG. 1;

FIG. 3 is a plan view, with a part cut away, showing certain parts ofthe needle bar device;

United States Patent ice FIG. 4 is a combination of an elevational viewand a perspective view showing the needle bar assembly;

FIG. 5 is a sectional view taken along the plane indicated by line V-Vin FIG. 4;

FIG. 6 is a perspective view showing the relative positions of a needleholder and the control cam;

FIG. 7 is a diagram showing examples of stitching patterns which can bereadily sewn by the use of the device of the invention;

FIG. 8 is an elevational view showing a needle suitable for use in thedevice of the invention; and

FIG. 9 is a top plan view of the needle shown in FIG. 8.

Referring tothe drawings, the needle-bar device em-, bodying theinvention is disposed at the left end of the arm of a sewing machine andis provided with a tubular needle bar 1 having an axial through hole inwhich a thin shaft 2' is slidably inserted. At the lower end of theneedle bar 1, there is fixed a flat plate 1 extending toward the rear ofthe sewing machine. On the bottom surface of this flat plate 1', thereare pivotally supported by pins 1" left and right needle chucks orholders 11', 11, 11" each having an inverted L shape and having a smoothupper surface. These holders are so supported that each holder can beswung open individually about the pin 1" as a pivot.

The thin shaft 2' inserted in the hollow interior of the needle bar 1has a cam 2 fixed to its lower end. The cam 2 is disposed between theleft and right needle holders of inverted L shape and is in contact withcontact surface 11" of each holder, whereby needles 13 and 13' held atthe front ends of the needle holders are respectively caused to swinghorizontally to the left and right by the rotational displacement of thecam 2.

Leaf springs 20, 20 each anchored at one end to the fiat plate 1' by ascrew 22, impart inward forces on the outer side surfaces of the holdermembers 11', 11' tending to swing the members 11', 11' toward eachother, whereby the needles 13 and 13 held by the needle holders areurged toward each other.

Each needle holder is provided with a groove partly formed in the member11 and partly in the clamp member 11", the flat tang F of a needle beingfitted into this groove and clamped in place at its rounded side edges13", 13 by a clamping force exerted by a clamp screw 12 by way of theclamping member 11 as best shown in FIGS. 5 and 6.

As shown in FIGS. 8 and 9, each needle for use in the device of theinvention is a round needle provided at its securing end with aflattened tang F which has a thickness equal to the diameter of theneedle shank 13. Therefore, when the left and right needles are placedin contact with each other, the two needle shanks can be positioned veryclose together as shown in FIG. 4, and the space between the left andright stitches can be reduced to a minimum as indicated in FIG. 7. Thereduction of this space, that is, the part left unstitched, to a minimumnot only is convenient but contributes to the production of estheticallypleasant stitching patterns.

Above the contact surface 11" of each needle holder, there is formed aflange 23 which rests on the upper surface of the cam 2, wherebywobbling during operation of the needle holder 11 which would otherwisebe in an unstable state of being supported at only its pivot pin 1" isprevented.

The tubular needle bar 1 is provided at its upper part shaft 2 is formedwith a square cross section. This square part 2" of the shaft isslidably fitted in a central square hole in a rotating bearing 6 engagedwithin a tapped hole in the upper end of a needle-bar guide tube 5provided at the left end of the sewing machine arm. The square shaftpart 2 slides up and down within the square hole as it moves togetherwith the ascending and descending needle bar 1.

The square hole, rotating bearing 6 is provided at its upper end with anarm 6, to which the displacement of a connecting rod 7 caused by amechanism (not shown) for producing needle oscillation for zig-zagsewing is transmitted, whereby the bearing 6 undergoes reciprocatingrotational movement.

When a sewing machine provided with the above described needle bardevice is operated, the needle bar 1 undergoes vertical reciprocatingmotion, and the squarehole rotating bearing 6 varies its twisting anglewhen a variation is produced in the amplitude of the movement of theconnecting rod 7 due to the cam (not shown) of the zig-zag producingmechanism (also not shown). Accordingly, the shaft 2", 2 fitted in thesquare hole undergoes twisting motion, whereby the cam 2 at the lowerend of the shaft 2 causes the needle holders 11, 11 in contact therewithto undergo left and right, opening and closing, oscillatory motion in asynchronous manner as indicated by arrows in the drawings. As a result,the two needles 13 and 13 held also are caused to oscillate left andright, thereby to sew stitch patterns, as shown in FIG. 7, which aresymmetrical left and right.

By using threads of two colors for the left and right symmetricalpatterns, uniquely beautiful patterns can be readily stitched, wherebythe versatility of zig-zag sewing machines can be further broadened.

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and that it isintended to cover all changes and modifications of the example of theinvention herein chosen for the purposes of the disclosure, which do notconstitute departures from the spirit and scope of the invention as setforth in the appended claims.

What I claim is:

1. In a sewing machine of the type having a main driving mechanism and amechanism for producing zigzag movements, a double-needle actionneedle-bar device comprising a tubular needle bar driven in verticalreciprocating motion by the main driving mechanism; needle holding meanscomprising a horizontally disposed flat plate fixed ot the lower end ofthe needle-bar device and extending rearwardly, moving verticallytogether with the needle bar, and left and right needle holders inparallel and symmetrical disposition adapted to hold two needlesconstantly in vertical alinement parallel to said motion of the needlebar but with freedom to undergo motion horizontal and transverse to theprincipal sewing direction of the machine; each said needle holder beingpivoted at its rear end by a pin supported by the rear end of the fiatplate so as to be free to undergo horizontal oscillatory motion towardand away from the other needle holder; said needle holders verticallyholding respective needles; a drive transmission comprising a thin shaftinserted within said tubular needle bar and provided, at its lower end,with a cam to cause said oscillatory motion of each needle holder; anddrive means to drive the thin shaft in accordance with said zig-zagmovements.

2. A sewing machine needle for use in the device of claim 1, each ofsaid needles having a flat tang of a thickness equal to the diameter ofthe shank or working part of the needles.

References Cited UNITED STATES PATENTS 710,696 10/1902 Klemm 112-158875,617 12/1907 Parkes 112158 1,503,921 8/1924 Sharaf 112-158 1,767,9556/1930 Armstrong 112-158 FOREIGN PATENTS 1,258,186 2/ 1961 France.

JORDAN FRANKLIN, Primary Examiner.

R. J. SCANLAN, Assistant Examiner.

1. IN A SEWING MACHINE OF THE TYPE HAVING A MAIN DRIVING MECHANISM AND AMECHANISM FOR PRODUCING ZIGZAG MOVEMENTS, A DOUBLE-NEEDLE ACTIONNEEDLE-BAR DEVICE COMPRISING A TUBULAR NEEDLE BAR DRIVEN IN VERTICALRECIPROCATING MOTION BY THE MAIN DRIVING MECHANISM; NEEDLE HOLDING MEANSCOMPRISING A HORIZONTALLY DISPOSED FLAT PLATE FIXED TO THE LOWER END OFTHE NEEDLE-BAR DEVICE AND EXTENDING REARWARDLY, MOVING VERTICALLYTOGETHER WITH THE NEEDLE BAR, AND LEFT AND RIGHT NEEDLS HOLDERS INPARALLEL AND SYMMETRICAL DISPOSITION ADAPTED TO HOLD TWO NEEDLESCONSTANTLY IN VERTICAL ALINEMENT PARALLEL TO SAID MOTION OF THE NEEDLEBAR BUT WITH FREEDOM TO UNDERGO MOTION HORIZONTAL AND TRANSVERSE TO THEPRINCIPAL SEWING DIRECTION OF THE MACHINE; EACH SAID NEEDLE HOLDER BEINGPIVOTED AT ITS REAR END BY A PIN SUPPORTED BY THE REAR END OF THE FLATPLATE SO AS TO BE FREE TO UNDERGO HORIZONTAL OSCILLATORY MOTION TOWARDAND AWAY FROM THE OTHER NEEDLE HOLDER; SAID NEEDLS HOLDERS VERTICALLYHOLDING RESPECTIVE NEEDLES; A DRIVE TRANSMISSION COMPRISING A THIN SHAFTINSERTED WITHIN SAID TUBULAR NEEDLE BAR AND PROVIDED, AT ITS LOWER END,WITH A CAM TO CAUSE SAID OSCILLATORY MOTION OF EACH NEEDLE HOLDER; ANDDRIVE MEANS TO DRIVE THE THIN SHAFT IN ACCORDANCE WITH SAID ZIG-ZAGMOVEMENTS.